Cigarette smoking is a prevalent and costly behavior that is estimated to kill over 440,000 people in the United States every year (CDC, 2008a). Rates of cigarette smoking are particularly elevated among individuals with psychopathology (CDC, 2008a). Within this category of individuals with psychopathology, individuals with Social Phobia (SP) represent a large group with elevated rates of cigarette smoking who quit smoking at rates lower than that of individuals without psychopathology (Lasser et al., 2000; Ruscio et al., 2008). These findings highlight cigarette smokers with SP as a particularly important group for further examination. For individuals with SP, cigarette smoking may be used to reduce feelings of social anxiety in anticipation of and during social situations and may also be used to increase contact with other smokers (McCabe et al., 2004; Wittchen, Stein, & Kessler, 1999). Two existing prospective longitudinal studies suggest that a relationship between SP and cigarette smoking exists and that this relationship may be temporal in nature such that SP and SP symptoms predict the onset of nicotine dependence (Breslau, Novak, & Kessler, 2004; Sonntag et al., 2000). Despite this relationship, no studies to date have experimentally examined the functional relationship between SP and cigarette smoking in order to determine if cigarettes are being used in this manner by individuals with SP to reduce anxiety in anticipation of social situations or in response to stress associated with these situations. Considering the long-term consequences of cigarette smoking, it is important to get a clear understanding of the functional relationship between cigarette smoking and SP in order to create targeted interventions and cessation programs in the future for individuals with SP. Towards this end, the proposed study examines the relationship between level of SP (high SP, healthy control with average SP) and cigarette smoking-related outcomes (smoking topography, cigarette craving, relative reinforcement efficacy (RRE) of a cigarette) as a function of induced social stress (neutral, stress). Additionally, the current study examines negative reinforcement expectancies (NREs) as a moderator of the relationship between SP and smoking outcomes.